ENDO, 04/2012

Aim: This in vitro study evaluated coronal leakage of endodontically treated teeth submitted to post space preparation and cementation procedures without rubber dam. Materials and methods: Of the 30 instrumented maxillary anterior teeth, 20 were filled (experimental group) and prepared for post placement. Using a bacterial leakage model, the experimental group's coronal tooth portions were exposed to a culture of Enterococcus faecalis for 30 mins, and glass fibre posts were subsequently cemented to seal the teeth. The apical portion remained in contact with the uncontaminated culture medium for 30 days, which turned cloudy when infiltration occurred. Ten teeth comprised the positive and negative control groups. The data were tabulated and statistically analysed according to the Kruskal-Wallis test (P 0.01), followed by application of the Wilcoxon test. Results: Contamination was observed in two samples after 9 days, corresponding to 10% of the experimental group, with no significant difference between the experimental group (EG) and the negative control group (NCG). Conclusion: The possibility of bacterial leakage exists when post space preparation procedures are conducted in unsterile conditions resulting from failure to maintain the aseptic chain. Keywords: dental leakage, post and core technique, rubber dams

Aim: This study compared the ability of three retreatment approaches, one of them using a supplementary step with the self-adjusting file (SAF), to remove filling materials from the apical root canal. Material and methods: Sixty incisors and canines were endodontically treated and distributed into three groups. The filling materials were initially removed by using D-RaCe instruments. In group Kosl, canals were enlarged up to one size larger than the first one to bind at the working length using a hand K-file; In group Kss/SAF, canals were prepared with a K-file of the same size of the apical canal and then the SAF instrument was used for 2 mins. In group Hss/Kosl, canals were instrumented with a Hedström file of the same size of the apical canal in circumferential filing motion and then enlarged one size larger with a K-file. The roots were longitudinally split and the canals were analysed under a stereomicroscope. The percentage of apical cleaned area was calculated. Results: The results indicated that the three protocols were similarly effective in cleaning (P > 0.05). Total removal of the filling material was rarely observed. Conclusions: During retreatment of relatively straight canals that are circular in cross section, there appears to be no further benefit in performing a supplementary step with the SAF instrument or filing with Hedström files after enlarging the apical root canals up to one size larger than the first instrument to bind at the working length. Keywords: cleaning ability, gutta-percha removal, Hedström files, root canal retreatment, self-adjusting file

Aim: This study aims to evaluate the prevalence of three-rooted permanent mandibular first molars in an Indian population. Materials and methods: The intraoral periapical radiographs of 616 patients of Indian ethnicity possessing bilateral mandibular first molars were screened under optimal conditions. A total of 1232 mandibular first molars were evaluated, and the prevalence of three-rooted mandibular first molars and the correlation between left and right side occurrence and between either gender was recorded. Results: The prevalence of three-rooted mandibular first molar was 16.07% of the patient's examined and 11.52% of the teeth examined. There was neither a statistically significant difference amongst the gender nor on the side of occurrence (P > 0.05). The bilateral incidence of a symmetrical distribution was 43.43%. Conclusion: Based on the results of the study, the prevalence of this anatomic macrostructure in an Indian population was 11.52%. Keywords: dental anomalies, mandibular molars, radix entomolaris

The root canal treatment of mandibular premolars is challenging due to their aberrant root canal anatomy and morphology. These teeth usually have a single root and a single canal, but anatomic variations can occur. The successful non-surgical root canal treatment of such teeth requires the basic knowledge of root canal anatomy and variation from the norm. The presence of an extra root or the extra canal is difficult to detect in periapical radiographs and overlooked root canals may lead to failure of the root canal treatment. This case report describes the use of spiral computed tomography (SCT) in confirmatory diagnosis and the root canal treatment of a mandibular second premolar with three roots and four canals. Keywords: anatomic variations, mandibular premolar, spiral computed tomography

Aim: The purpose of the present study was to assess the push-out bond strength of three furcation perforation repair materials: MTA, BioAggregate and IRM. Materials and methods: Forty-five extracted human mandibular first molars were used in this study. Their roots were amputated 3 mm below the furcation and standardised access cavities were prepared in all molars. Furcation perforations of 1 mm diameter were performed between mesial and distal roots. The molars were divided into three groups (n = 15) according to the type of perforation repair material used. Group I was repaired with ProRoot MTA, group II was repaired with BioAggregate and group III was repaired with IRM. After setting, the samples were mounted in a loading fixture and each repair material was subjected, in an apical-coronal direction, to a compressive load with a load cell of 5 KN at a cross head speed of 1 mm/min with a 0.8 mm diameter plugger via a universal testing machine for the push-out bond strength measurement. Results: There was no statistically significant difference between the push-out bond strength values of the three tested materials (P > 0.05). Conclusions: It can be concluded that BioAggregate showed push-out bond strengths comparable to other commonly used root repair materials in small size cavities. Keywords: BioAggregate, furcation perforation, IRM, MTA, push-out bond strength

Evidence-based dentistry (EBD) is a ubiquitous term, commonly found in research publications, appearing in books and included in manufacturers' sale literature. What really is EBD? Is the term being applied correctly? Do readers have a proper understanding of its meaning? Is the term used purely to render support and to make claims more scientific sounding? This easy-to-follow article is intended to demystify and to serve as an introduction to EBD, to provide an explanation of the background process of searching, appraising and applying the evidence to everyday clinical practice. By understanding the EBD approach, it will empower clinicians to question and consider the use of current best evidence in decision-making on the management of individual patients and, ultimately, lead to improved treatment outcome. Keywords: EBD, endodontics, research

Aim: Bacterial growth into obturated root canals may occur when coronal restorations are lost or their seal compromised. The aim of this study was to test the hypothesis that incorporation of quaternary ammonium polyethyleneimine (PEI) nanoparticles into endodontic sealers will render them antibacterial properties so that they may prevent such bacterial growth. Materials and methods: PEI nanoparticles were incorporated at 2% w/w into AH 26 and AH Plus or Roth's and Pulp Canal Sealer (PCS) sealers. Antibacterial activity of the sealer surface against Enterococcus faecalis was measured immediately after setting and after ageing for 4 weeks, using the Direct Contact Test. Results: All four PEI-containing sealers presented high early antibacterial properties that were fully maintained after ageing for 4 weeks. None of the original unmodified sealers presented such activity after ageing (P 0.001). Conclusions: PEI nanoparticles may be used to induce stable antibacterial properties in the surface of both epoxy-based and zinc-oxide-eugenol-based endodontic sealers. Keywords: antibacterial, DCT, endodontic-sealer, E. faecalis, nanoparticles, PEI

Introduction: External root resorption occurs as a consequence of trauma to the periodontal attachment apparatus. This damage can be induced by trauma, orthodontic therapy, surgical procedures or periapical inflammation. Healing of the external root resorption can only be achieved by finding and therapy of the particular stimulus. Methods: The present case describes external root resorption of two vital teeth caused by a large lesion of endodontic origin associated with an adjacent non-vital molar. Results: Treatment of the endodontic pathosis resulted in healing of the external root resorption and the lesion of endodontic origin. Conclusions: A lesion of endodontic origin can provoke periapical lesions on adjacent teeth. Standard endodontic diagnostic steps are absolutely essential. Inadequate preliminary diagnosis or prognosis assessment can result in endodontic failure. Keywords: endodontic lesion, external resorption

Introduction: This case report describes a mandibular second molar with four roots - three distal roots (distobuccal, middle distal, distolingual - DB, MD and DL, respectively) and one mesial root and five root canals (mesiobuccal, mesiolingual, distobuccal, middle distal, distolingual - MB, ML, DB, MD, DL) diagnosed with spiral computed tomography. Case report: A 33-year-old male reported pain in the mandibular left back tooth. On radiograph, the mandibular left second molar revealed an unusual root morphology. On spiral computed tomography, four roots and five canals were confirmed. Root canal treatment was then completed successfully. Conclusion: Although incidence of these variations is uncommon, the clinician must be aware of unusual root morphologies. Keywords: dental anatomy, distal root, endodontic treatment, mandibular second molar, spiral computed tomography